1. Field of the Invention
The present invention relates to a roof member incorporating a solar cell. More particularly, the invention concerns a roof member easy to install and excellent in electric safety and an electrically grounding method of a metal reinforcing member of a combination solar cell and roof member.
2. Related Background Art
In use of the solar cell the durability is required against influence from the external environments such as the temperature, the humidity, or impact. Therefore, the ordinary solar cell modules are constructed in such structure that a photovoltaic element is sealed in a filling material, the surface is covered with a weather-resistant film or glass as a protective material, and a metal reinforcing member is attached to the circumference or the back surface.
In terms of the electric safety, in order to avoid the worst case of electric shock when a man touches a part of the metal reinforcing member being the outside part of the solar cell module, a method for electrically grounding the outside part of solar cell module has been adopted heretofore.
FIGS. 13 and 14 show a conventional frame mount type solar cell device.
As seen in FIG. 13, the solar cell module array of this conventional example is constructed of a plurality of solar cell modules 1301 fixed to frame 1302.
As shown in the cross-sectional view of FIG. 14, a solar cell module used in this conventional example is constructed in such structure that a solar cell element 1401 is sealed in resin 1404, the top surface is protected by glass 1403, the bottom surface by weather-resistant film 1402, and an aluminum frame 1405 for reinforcement and mounting to the frame is attached to the circumference.
The electric grounding of such solar cell modules of the conventional example will be described referring to FIG. 14. In order to achieve electric conduction of the three members of the aluminum frame 1405 attached to the solar cell module, stainless-steel bolt 1407, and stainless-steel frame 1406 through the stainless-steel bolt 1407, a cable is attached to a part of the frame 1406 set on the roof and the cable is electrically grounded, thereby achieving the electric grounding of each solar cell module.
There is, however, no practical method developed yet for electric grounding of the metal reinforcing member adapted for a roof member and solar cell combination incorporating a roof member and a solar cell element without the frame described above. It is needless to mention that a method for providing each module with a cable for electric grounding greatly increases the cost and lowers the work efficiency, thus posing a problem.
The present invention provides a specific method for electric grounding of a combination solar cell and roof member (a solar-cell-incorporated roof material) installed on the roof.